IMECH-IR  > 非线性力学国家重点实验室
Alternative TitleNovel Voronoi Structural Design and Its Mechanical Properties
Thesis Advisor许向红
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Discipline材料工程
KeywordVoronoi算法 多孔结构 梯度设计 抗拉性能 吸能效率





Other Abstract

Two-dimensional cellular structure is one of the most widely used structures in engineering because of its light weight, high specific strength, excellent sound insulation and energy absorption characteristics. According to the different application environments and the same relative density, three different optimum design schemes are proposed. Based on the theoretical analysis and numerical simulation results, the differences between the performance of these optimum structures and traditional structures in tension resistance, cushioning and energy absorption are explored. Subject research can be divided into:

Under uniaxial static tension, the gradient grid random distribution method for Voronoi polygon generation is proposed for the first time, which realizes the non-uniform design of cell size in the whole model area. The static uniaxial tension load is applied to the cellular structure. The results show that the uniaxial tension performance of gradient cellular structure is better than that of uniform structure when the relative density is equal. With the increase of gradient coefficient, the reinforcement effect is more obvious. The structure with small cell size at upper and lower edges has the best tensile capacity, and the tensile performance of gradient structure can be improved by 70.5% as compared with that of uniform structure.

Under the loading condition of dynamic impact, the model of positive and negative gradient distribution of cell size is designed in this paper. By comparing the energy absorption efficiency, it can be found that the impact velocity is positively correlated with the energy absorption efficiency. There is a negative gradient model, a positive gradient model and a uniform model for the energy absorption efficiency between the models. At the same time, based on the traditional one-dimensional shock wave model, a shock wave model suitable for gradient structure is proposed, and the essential reason for the difference of energy absorption efficiency between the models is explained from the difference of relative density behind the wave front. The correctness of the proposed model is verified by comparing the theoretical solutions and finite element results of the platform stress at the impact end.

Based on the background of fiber composites and introducing reinforcing materials and matrix materials, this paper designs a fiber orientation layout model. By comparing with Voronoi structure of reinforcing body centralized layout model and short fiber random uniform distribution model, the long fiber orientation distribution model has higher load-carrying capacity than the reinforced body centralized layout model and the short fiber random uniform distribution model, respectively. It was 45.12% and 36.9% higher. Under the impact load of 3m/s, the energy absorption of the cellular structure of the long fiber oriented distribution model is 32.6% and 29.3% higher than that of the reinforced body concentrated arrangement model and the short fiber random uniform distribution model, respectively. By comparing the models of different fiber lengths, it is found that the ratio of single fiber length to total fiber length in the model is in the range of 70% to 80%, which can ensure the compressive stability of the cellular structure itself.

Call NumberMas2019-003
Document Type学位论文
Recommended Citation
GB/T 7714
顾洋. 新型Voronoi结构设计及其力学性能研究[D]. 北京. 中国科学院大学,2019.
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